Player creating either local random game or a multiplayer one who selects this option will then get send to the Upgrade screen. Player can select _at each upgrade_ if that upgrade can or can't be used during the game. Player can allow even not-yet-unlocked upgrades but won't see what are they offering to not spoil the upgrades. Anyone can see what upgrades are unlocked in given game, so joining players can check this before they join.
Lite version of this idea may be coming up with, say, at least 3 new upgrade modes. Those would not be player-set-able but standardized, with list of upgrades they allow listed in the Help. They would be located between "NO" and "YES(0)" on the list of upgrade modes: NO, SOME1-0, SOME2-0, SOME3-0, ALL0, ALL5, ALL10.
These three (or different number up to like 5) could be something like:
- allows only the factory buildings (archery range, stables, siege engine workshop, church)
- allows all that and castles and all other upgrades (except Tfighter and spells) from page 1 of Upgrades (few more units)
- allows all upgrades (except Tfighter and spells) from the first 3 pages of Upgrades (weapon upgrades, unit upgrades)