er.. Bro Tikiram, i dont know which sifu Wong, i'm see-food (sure eat) Wong OR MK (Makan Kenyang)

, but i've some ideas
FYI - i'm also in my early 40s, sama-sama

Ideas to try out, since you're a trained number cruncher + Excel wielder (my main weapon of choice, sure die in a gun/knife fight

), much easier for U to see the logic.
RATIOS or % for each type of spending.
Ratios or % are same no matter one earns $100K or $1M, thus, it's consistent right?
Simple Method ASave & invest XX% of your net salary/"man-at-work" income (investment returns no no touch)
Spend the rest - dont care, just enjoy
Simple enough? I'd suggest the save & invest of at least 10%, preferably up to 30% or more in total (including windfalls like vitamin B-onus

).
Note, if U really want to prioritize balance of feel good VS future, then 20%+/- should be enough.
Me - i'm rebuilding hehe.
Specific % Method - idea copy, modded and used from T Harv Ekar - it WORKS for anal retentive / number focus people like me 
a. <=50% or lower for necessities
b. >=10% for savings for debt repayment and/or emergency buffer, once hit goal, add into investments &/or feel good
c. >=10% for investments
d. >=10% for feel good - break this down perhaps 50% for self fun, 50% to see others have fun, OR 1/3 for me, 1/3 for family, 1/3 for charity OR up to U in %
NOTE - U have to use it (d.) up every month! hheheh
Please balance (d.) and (c.) or else U may either be having too much VS U may be too scrooge-like
e. >=10% for education (self, children, etc.) - books, computers for school/college/training/workshop/etc.
f. >=10% for spending in future - to accumulate for that new iPhone U want OR new car OR whatever big or BIG ticket items that your "feel good" can't cover
The main idea for the specific % is lower your necessities (in comparison to your net income + net bonuses) and increase the rest.
Looks FAIR right in % - equal amount of (c.) and (d.) - balance of feel good + investing for the future
AND
If U ratio the (d.) to how much of % goes to U, % to family, % to friends & charity - U are then "fairer" to all (based on your priorities lar). Right or right?
How i execute?
Simple - i have all these in my Flexi Mortgage but i track via Excel hehe
Splitting my Flexi Mortgage into several columns, thus i can track
+ as i use, i track my expenditure to the nearest $10+/- based on the above 6 categories
Told U i was crazy but it work for me coz it's all so VISUAL.
Just thoughts to bounce around with U, no right/wrong yar
PS:
Although i loved the book, i didn't attend T Harv Ekar's "seminars". They seem to be more ra-ra to me lar. Reading more effective and cost effective to me - i'm just made "like that" heheh.
Thank you sifu for the valuable input & sharing.
In my opinion, you are a wise person. Example using the flexi mortgage to help tracking and the "<= " and the ">=" ratio work for the flexiblity.
The rules of below is new to me and it almost solving my main problem of " not spending enough for myself"
You have answer my query. Many thanks from me