Is boost converter enough to provide pulse currents without drawing too much current from a coin cell
First some rules of physics.


All loads have an equivalent impedance for each state.
All batteries like electrolytic capacitors have an Effective Series Resistance (ESR) and Capacitance , C [F] where the change in capacitance can be measured in Ah or mAh  
the product of ESR *C is a function of cell chemistry and bulk size and may be used to compare.
any DC supply voltage in a somewhat linear mode will drop voltage according to the resistive divider or Load Regulation formula.  


Vdrop = I * ESR = Vo-Vi = ESR/(ESR+Load). 
where desired is ESR &lt; 1% R load for performance reasons. 
ESR rises rapidly below 10% state of charge (SoC) and rises slowly with aging effects ( heat, under/over charge , cycles, ambient temp)

for any given chemistry (primary or secondary) the ESR is inverse to Ah capacity ( for a single cell)
ESR multiplies for cells in series *(S) and divides for cells in parallel (P) and  all must be matched. 
Hybrids may be S x P arranged for suitable voltage and current and thus source impedance.
All electrolytic caps and batteries have memory such that after a short, they return to a resting voltage. - This is a secondary ESR2*C2 equivalent circuit. There may be more.
Compute the energy loss in a large cap and see if that is worth buffering the ESR. 


E=1/2 CV^2=VI*t



Now go choose a battery that has an acceptable Vdrop and Capacity at desired load current.. 

Converters do not add energy, mainly change impedance ratio.  BE conservative.