Having been through all of this many times -
some more food for thought
The landing gear
You simply can NOT beat wire for strength to weight and shock absorbing
fibreglass is the worst.
carbon fibre is light but lousy on shock absorbing
Foam wing - don't try i unless you have done a bunch of em - for this type plane, the open structure is easily best weight to strength Ihave personally done a least 1000 foam wings -of all types (I built n sold custom stuff fo almost 30 years.)
For power - the setup on the Seniorita shown is a .20 K&B with stock muffler as quiet as most electrics - That model is 4 pounds flying weight and all kit wood was used.
A really nice easy flyer and will loop at full speed in level flight (just barely) The airframe -without any hardware -but completed was - 3 lbs.
You can easily do the plane you wnt at 4 lbs
then add hardware
You can NOT add expensive lighter components to make a lighe model
Many try it and just blow a lot of money for very little return.
You start with a set of scales and a plan for the finished weight -
Hope, just won't do the job. The Cap in the picture is 13+pounds and 1100 squares with a 40ccengine and a carbon fibre tuned exhaust-and 7075T6 cystom made gear - it has solid foam panes on all surfaces and an all balsa fuselage it LIGHT by any standards.
That construction was done for again-best strength to weight - The model is an all out 3D /pattern setup
I mention this to show the different approach-for different tasks